I don't have the experience with a Trophy as many of the others but unless you have an issue with bad/old firmware for the radio I suspect 10 days is nothing. However if you have a battery maintainer/tender I don;t think ti would hurt to attach it.

As mentioned by st1371 unless you have an older version of the audio software 10 days is not an issue. I just came back from 10 days in Colorado no problems, you have to consider that each day I was riding 7 - 8 hours a day so the battery should be fully charged each day's end.

I won't be using the bike for 10 days (I know!) so, do I need to put it on a battery tender or will it last the 10 days? Cheers.

Depends on the condition of the battery. A new battery will have no problem with ten days of non-use. All bets are off with an older battery.

But with either a new or old battery, a battery maintainer is best. It will turn on and off automatically as necessary to keep the battery fully charged without overcharging. Should have one to two amps charging current when on. If a choice, I would go for the one amp.

If the bike is left outside where there is sunlight, you can use a small solar charger. If the days are long and sunny and left for a long time, I might also consider adding a small solar controller to prevent over charging. But most likely wont be necessary with the 1.5 watts max that the solar panel can put out.

As mentioned by st1371 unless you have an older version of the audio software 10 days is not an issue. I just came back from 10 days in Colorado no problems, you have to consider that each day I was riding 7 - 8 hours a day so the battery should be fully charged each day's end.

Funny, I just came back from 9 days mostly in Colorado, but riding my '17 Trophy, and having a blast touring the Rockies. My '13 Trophy stayed home, and adding a week on top of that it still started with no hesitation. I have a Battery Tender, but rarely find a need to use it.

I haven't used my Battery Tender in quite a while, and it has sat for 2-3 weeks in between rides for various reasons and never had an issue with starting. Of course that's after the radio software update that left me with a dead battery twice before it was a year old. That was 3-1/2 years ago. I have plugged it in when there was going to be an extended trip and it had to stay home. Had a friend come ride it once while I was gone to England so it didn't get too lonely!

Im thinking that with the Triumph - Datatool optional security system installed (my Trophy has it), one should be ok if the bike sat for a month. Without the Datatool device installed (or either set to Winter mode) I would think one would be good for 3 months at least without starting - speaking from experience with two Sprint STs. Removed the Datatool device from my current Sprint last year due to internal battery failure. Seriously considering replacing it if the price is right.

A bit of trivia: if one wants 4 way flasher function on the Sprint between 2003 and 2009 (U.S. models) then one MUST install the Triumph-Datatool security system, and then it only functions through the Datatool key fob with the motor turned off - never understood the reasoning behind this except to sell more Triumph-Datatool units.